Method for detection and enabling of an evasive manoeuver in a vehicle with an automated manual transmission

ABSTRACT

A method of detecting and enabling an evasive manoeuver in a vehicle with an automated transmission, in which initially the method checks whether the reverse (R) drive is engaged, and checks whether the steering-wheel angle and the steering-wheel angular velocity are valid and in excess of threshold values. If so, a first timer is started and then the method checks to see if the yaw rate and the transverse acceleration of the vehicle exceed threshold values while the first timer is running, and when the yaw rate and the transverse acceleration of the vehicle exceed threshold values while the first timer is running, a driver&#39;s wish to carry out an escape turn is recognized and a second timer is started, and both timers have not yet run their course, the speed threshold for permitting engagement of the forward drive (D) is increased to exceed the normal threshold value for permitting engagement of forward drive (D) is a is a set is positioned.

This application claims priority from German patent application serial no. 10 2012 214 497.8 filed Aug. 14, 2012.

FIELD OF THE INVENTION

The present invention concerns a method for detecting and enabling of an evasive manoeuver in a vehicle with an automated transmission. In particular, the invention relates to a method for detecting and enabling of an evasive manoeuver in a vehicle with a dual-clutch transmission.

BACKGROUND OF THE INVENTION

In essence, a dual-clutch transmission comprises two strands or partial transmissions with various gearwheel pairs, two power-shifting clutches each of which is associated with a respective partial transmission, a drive input shaft and a drive output shaft, and interlocking, unsynchronized shifting clutches in accordance with the number of gears. In such a transmission the gears are arranged in alternation in the two partial transmissions, making it possible to preselect a gear in the load-free partial transmission while the drive torque is being transmitted by the other partial transmission.

A gearshift is carried out when the torque to be transmitted is transferred from one power-shifting clutch to the other so that the gears can be shifted while free from load, without traction force interruption and without stressing the shiftable gears. As a rule the odd-numbered gears can be shifted in one partial transmission and the even-numbered ones and the reversing gear in the other partial transmission.

From the prior art it is known, with vehicles having an automated transmission, to store speed threshold values in the electronic transmission control unit, such that a drive mode change from D to R or from R to D, which occurs for example during a parking or an un-parking process, can only take place if the speed of the vehicle is below the speed threshold concerned. This is intended to avoid mechanically damaging the transmission.

If a change of direction through 180° while driving rapidly in reverse is desired, i.e. a so-termed evasive manoeuver, it is thus disadvantageously not possible to engage the drive mode D. This can result in critical situations if it is necessary to carry out an evasive manoeuver for safety reasons.

SUMMARY OF THE INVENTION

The purpose of the present invention is to indicate a method whose implementation ensures that an evasive manoeuver is recognized and enabled in a vehicle with an automated transmission.

According to these, a method is proposed for detecting and enabling an evasive manoeuver in a vehicle with an automated transmission, in the process of which it is checked whether, when the R drive mode is engaged and valid sensor values are given for the steering-wheel angle and the steering-wheel angular velocity, predetermined threshold values for the steering-wheel angle and the steering-wheel angular velocity are being exceeded, and if the steering-wheel angle and the steering-wheel angular velocity are in excess of the predetermined threshold values, a first timer is started, and a driver's wish to carry out an evasive manoeuver is recognized if, with valid sensor values for the yaw rate and the transverse acceleration, the yaw rate and the transverse acceleration of the vehicle each exceed a respective predetermined threshold value while the first timer is running.

When a driver's wish to carry out an evasive manoeuver has been recognized, a second timer is started and the speed threshold for permissible engagement of the D drive mode is increased to a predefined threshold value which is higher than the normal threshold value for the permissible engagement of the D drive mode. According to the invention the new, higher value of the speed threshold for permissible engagement of drive mode D remains in force so long as the first and second timers have not yet run their course.

By virtue of the concept according to the invention, a driver's wish to carry out an evasive manoeuver is reliably recognized; in addition an evasive manoeuver can be carried out within a predefined time window.

In the case that a sensor value is transmitted by way of a data bus, for example a CAN-bus, the sensor value is recognized as valid as long as the status of the bus signal is in order. When a sensor value is read directly, the sensor value is recognized as valid if the sensor is operating normally and if it delivers a plausible signal.

The method according to the invention can be implemented, for example, in a vehicle with an automated transmission and an automated dual clutch.

BRIEF DESCRIPTION OF THE DRAWINGS

Below, the invention is explained in more detail with reference to a sole FIGURE of flow diagram which illustrates an example of the method according to the invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring to the attached FIGURE, at the beginning of the process it is checked whether the R drive mode is engaged, whether the sensor values for the steering-wheel angle and the steering-wheel angular velocity are valid, and whether the steering-wheel angle and the steering-wheel angular velocity are in excess of predetermined threshold values.

If all these conditions are met a first timer, Timer 1, is started and in a next step it is checked whether, if the sensor values for the yaw rate and the transverse acceleration of the vehicle are valid, the yaw rate and transverse acceleration are in excess of a respective predetermined threshold value while the first timer is running.

If that is the case, a driver's wish to carry out an evasive manoeuver is recognized and a second timer, Timer 2, is started, and provided that the first and second timers have not yet run their course the speed threshold for permissible engagement of the drive mode D is increased to a predefined threshold value which is higher than the normal threshold value for the permissible engagement of drive mode D.

Examples of threshold values for the yaw rate, the transverse acceleration, the steering-wheel angle and the steering-wheel angular velocity are, respectively, 50 degrees/s, 3 m/s², 300 degrees and 300 degrees/s, whereas the time window associated with the first timer can be 4000 ms and the time window associated with the second timer can be 2000 ms.

Furthermore, the increased speed threshold for permissible engagement of drive mode D can be 70 km/h; as a rule the normal speed threshold for permissible engagement of drive mode D is 7 km/h. 

1-3. (canceled)
 4. A method of recognizing and enabling an evasive manoeuver in a vehicle with an automated transmission, the method comprising the steps of: checking, at a beginning of the method, whether a reverse (R) drive mode is engaged, whether sensor values for a steering-wheel angle and a steering-wheel angular velocity are valid, and whether the steering-wheel angle and the steering-wheel angular velocity are in excess of predetermined threshold values, starting a first timer, if these conditions are met, and then checking whether sensor values for yaw rate and transverse acceleration of the vehicle are valid, and whether the yaw rate and the transverse acceleration of the vehicle are in excess of respective predetermined threshold values while the first timer is still running, and when (a) the sensor values for yaw rate and transverse acceleration of the vehicle are valid, (b) the transverse acceleration of the vehicle are in excess of respective predetermined threshold values, and (c) the first timer is still running, then recognizing a driver's wish to carry out the evasive manoeuver and starting a second timer, and provided that the first and the second timers have not yet run their course, increasing a speed threshold for permissible engagement of a forward (D) drive mode to a predefined threshold value which is higher than a normal threshold value for the permissible engagement of forward (D) drive mode.
 5. The method of detecting and enabling the evasive manoeuver in the vehicle with the automated transmission according to claim 4, further comprising the step of: transmitting the sensor values via a data bus and recognizing each sensor value as valid if a status of a bus signal concerned is in order, and when a sensor value is read directly the sensor value is recognized as valid if the sensor is operating normally and is delivering a plausible signal.
 6. The method of detecting and enabling the evasive manoeuver in the vehicle with the automated transmission according to claim 4, further comprising the step of using, as the threshold values for the yaw rate and the transverse acceleration, the steering-wheel angle and the steering-wheel angular velocity, respectively, 50 degrees/s, 3 m/s2, 300 degrees and 300 degrees/s, and using 4000 ms as a time span window of the first timer and 2000 ms as a time span window of the second timer.
 7. A method of recognizing and enabling an evasive manoeuver in a vehicle with an automated transmission, the method comprising the steps of: checking whether a reverse drive mode is engaged; checking whether a sensor value for a steering-wheel angle and a sensor value for a steering-wheel angular velocity are valid; checking whether the sensor value for the steering-wheel angle exceeds an associated predetermined threshold value and the sensor value for the steering-wheel angular velocity exceeds an associated predetermined threshold value; starting a first timer, if the reverse drive mode is engaged, the respective sensor values for the steering-wheel angle and the steering-wheel angular velocity are valid, the sensor value for the steering-wheel angle exceeds the associated predetermined threshold value, and the sensor value for the steering-wheel angular velocity exceeds the associated predetermined threshold value; checking whether a sensor value for vehicle yaw rate is valid and a sensor value for transverse acceleration of the vehicle is valid, and checking whether the sensor value for vehicle yaw rate and the sensor value for the transverse acceleration of the vehicle exceed respective predetermined threshold values while the first timer is still running; recognizing a driver desire to carry out the evasive manoeuver when the respective sensor values for the vehicle yaw rate and the transverse acceleration of the vehicle are valid and exceed the respective predetermined threshold values while the first timer is still running; starting a second timer; and if the first and the second timers have not yet lapsed, increasing a speed threshold, for permissible engagement of a forward drive mode, to a predefined speed threshold value which is higher than a normal speed threshold value for the permissible engagement of the forward drive mode.
 8. The method for detecting and enabling an evasive manoeuver in a vehicle with an automated transmission according to claim 7, further comprising the step of recognizing that the respective sensor values for the steering-wheel angle and the steering-wheel angular velocity and the respective sensor values for the vehicle yaw rate and the transverse acceleration of the vehicle are valid, when the sensor values are transmitted by a data bus, if the status of respective bus signals concerned are in order, and when the respective sensor values are read directly, the respective sensor values are recognized as valid if an associated sensor is operating normally and is delivering a plausible signal.
 9. The method for detecting and enabling an evasive manoeuver in a vehicle with an automated transmission according to claim 7, further comprising the steps of: defining the predetermined threshold value for the vehicle yaw rate as 50 degrees/s; defining the predetermined threshold value for the transverse acceleration as 3 m/s²; defining the predetermined threshold value for the steering-wheel angle as 300 degrees; defining the predetermined threshold value for the steering-wheel angular velocity as 300 degrees/s; and defining the time span for the first timer as 4000 ms and the time span for the second timer as 2000 ms. 